Sterilization cassette

ABSTRACT

A sterilization cassette has a slide latch system to secure the lid of the cassette to the body of the cassette. A finger tab on the outside of the cassette moves a latch arm on the inside of the cassette along a slot. A tension spring secures the position of latch components whether the latch is open or closed. Spacers between the cassette and latch parts facilitate smooth gliding action. The latch arm engages an angled bracket on the lid of the cassette. Alternating notch depths on instrument rails within the cassette work with opposing rails that likewise have alternating depths of notches to capture and hold instruments. This notch configuration causes the handles of adjacent instruments stowed in the cassette to stagger in height so that a clinician can access the handles of the stowed instruments.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending application Ser. No.12/635,211, filed Dec. 10, 2009, which claims the benefits of U.S.Provisional Application No. 61/201,438, filed Dec. 10, 2008, thedisclosure of which is hereby incorporated by reference in its entiretyincluding all figures, tables and drawings.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISC APPENDIX

Not applicable

FIELD OF THE INVENTION

This invention relates to a cassette and tray system wherein cassettesof varying sizes and internal configurations are used to securely holdcollections of dental/medical instruments. Such cassettes maintain asecure and orderly arrangement of desired instrumentation during theoffice procedure and/or particularly in the cleaning operation duringthe sterilization process.

BACKGROUND OF THE INVENTION

Sterilization cassettes are typically a square or rectangle box with abottom, or body and a mating lid; the lid is often held to the bottomwith a hinge. Traditionally most cassettes are made of stainless steelsheet material which has been perforated to allow sterilizing steam toenter the cassette. A cassette blank is bent to form a shallow sided boxwith the backside of the box often including hinge cleats. Box depth istypically ¾inch to 2 inches. The lid is similarly constructed. The lidcan also have a series of hinge cleats along one side. Sterilizationcassettes can also be made of resin. The lid and box are fastened to oneanother to trap instruments to be sterilized inside. Traditionally, thelid is connected to the box on one side by a hinge and fastened on theother with a clip or latch. Alternatively, the lid can be secured to thebox with an arrangement of slots and mating tabs. This allows the lid tobe removed from the box after sterilization. Deficiencies in thelatching or fastening mechanism used to secure the lid to the bottomcompartment cause a great deal of consternation in many availablecassette designs.

The interior of a cassette can contain a series of standoff rails tohold long instruments and divided compartments to hold small orinconsistently shaped instruments. Rivets and/or spot welding secure theinternal dividers and rails, or if the cassette is made of resin thesedividers are injection molded. Traditionally, instrument rails have somesort of scalloped design or extended fork slots in which to align andhold the instruments side by side in the bottom of the cassette. Mostcommonly these bottom rails are made of stainless steel or are asilicone strips attached to the bottom of the main compartment.Instruments are dropped into scalloped cradles in the rail or pressedbetween flexible silicone fingers on the silicone strip to securelyretain the instruments in the cassette. If stainless steel instrumentscalloped rails are used, a strip of silicone tubing is attached acrossthe lid, thereby providing a means to retain the instruments within thescalloped cradles when the lid is closed protecting the instruments fromdamage during the sterilization procedure. The scallops or fingers of arail are arranged to accommodate a maximum number of instruments. Thiscauses difficulty however when there is not enough space betweenneighboring instruments to allow the clinician to remove the choseninstrument in a safe manner. The clinician is forced to grab theinstrument by its sharp working end where there is adequate finger roomto remove it from the cassette. Sterility can be compromised if thesharp end cuts through the glove on a hand.

Current cassette lids use silicone exclusively as a means of retentionto hold instrument in place. It is becoming increasingly undesirable touse silicone in or on products that require sterilization. It has beenrecognized that silicone traps debris beneath its layer and shields orinsulates that debris from the effects of sterilization.

A need remains for a sterilization cassette with a reliable, easy to uselatching system with an internal configuration that holds instrumentsconveniently for the clinician yet holds them securely and without theuse of silicone.

All patents, patent applications, provisional patent applications andpublications referred to or cited herein, are incorporated by referencein their entirety to the extent they are not inconsistent with theteachings of the specification.

BRIEF SUMMARY OF THE INVENTION

A sterilization cassette is described that has a bottom compartment thathouses instruments in a compact side-by-side arrangement, yet allows theclinician to remove sharp instruments by their handles and not by theirsharp working tips. The height of instruments is staggered within ascalloped rail where one end of an instrument is up and the same end ofthe adjacent instruments are down. This arrangement creates a crisscrosspattern in the instrument racks allowing the clinician to grab aninstrument handle instead of grabbing the dental instrument by its tip.Additionally, the present invention does not use silicone as a retentionmeans to hold instruments in place within the closed cassette. Acontoured stainless steel retention rails and/or flat protruding springfingers affixed to the lid is used to secure and hold individualinstruments in place in the cassette of the subject invention. The useof a non-insulating material for retention, such as metal, allows for amore effective sterilization action.

A unique slide latch design made of stainless steel mated withpolytetrafluoroethylene slides allows the latch arm to smoothly engage astainless bracket on the lid of the cassette. The components of theslide latch are assembled about an elongated slot in the front bottom ofthe box. A finger tab or thumb knob positioned on the front of the boxis secured to a metal latch arm inside the box. Sandwiched between thefinger tab and the latch arm is a spring tempered tension washer. Apiece of polytetrafluoroethylene slide is positioned between the fingertab and the front of the box. A second polytetrafluoroethylene slide ispositioned between the latch arm and the inner box front wall. An anglebracket is affixed onto the lid to engage the latch arm and complete thelatching system.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a perspective view of a preferred embodiment of asterilization cassette of the subject invention showing the front fingerslide tabs and securing right angle bracket affixed to the lid.

FIG. 2 is an exploded view of a latch element on a preferred embodimentof a sterilization cassette of the subject invention.

FIG. 3 is a cross-sectional rear view of a preferred embodiment of asterilization cassette showing the interior of the box and the latch inthe open position.

FIG. 4 is a cross-sectional rear view of a preferred embodiment of asterilization cassette showing the interior of the box and the latch inthe closed position.

FIG. 5 is a perspective view of a preferred embodiment of thesterilization cassette of the subject invention showing a preferred railconfiguration.

FIG. 6 is a side perspective view of instruments in a preferredembodiment of the sterilization cassette of the subject inventionshowing the staggered positioning of the instruments in the rails.

FIG. 7 is a cross-sectional side elevational view of a preferredembodiment of the sterilization cassette of the subject invention theclosed cassette showing angled rails on the bottom of the cassettematching angled retention rails on the lid of the cassette.

FIG. 8 a cross-sectional side elevational view of another preferredembodiment of the sterilization cassette of the subject invention theclosed cassette showing straight rails on the bottom of the cassettematching straight retention rails on the lid of the cassette.

DETAILED DESCRIPTION OF THE INVENTION

The invention involves an improved sterilization cassette with an easilyengagable latch to lock instruments to be sterilized within thecassette. A unique rack system securely holds the instruments in thecassette without using silicone, yet presents the handles of theinstruments to the clinician for easy removal from the cassette.

The latch assembly for use on the cassettes of the subject invention isa slide latch that is easy to use yet securely keeps the lid closedunder the most extreme handling conditions. A preferred embodiment ofthe subject latch system is shown in FIGS. 1-4. Stainless steel is thepreferred material for the slide latch, however any metallic material,such as titanium, or aluminum with a protective hard coating, orresin/plastic, and nylon can be used. Materials for the latch arepreferably all non-insulating materials. The locking slide latch orsimple slide latch slides to engage an accommodating bracket secured tothe lid 12 of the cassette. A thumb grip or finger tab is positioned onthe outer front 14 of the main body 10 of the cassette. One skilled inthe art would recognize that the sliding latch system of the subjectinvention could be located on the sides 16, 18 of the cassette body aswell, and still function effectively. The finger tab 20 is attached toan internal latch arm 22 through a slotted hole 24 by, for example,riveting, spot welding, screws, welding, or brazing. A spacer 26 isdisposed between the finger tab 20 and the outside wall of the front 14of the body of the cassette and an opposing spacer 28 is positionedbetween the latch arm 22 and the inside wall 29 of the front of thecassette to provide a smooth sliding action. The spacers can be anymaterial that facilitates slide yet is resistant to the sterilizationprocess. In a preferred embodiment, the spacers are rectangular piecesof polytetrafluoroethylene. A tension spring 27 is positioned betweenspacer 28 and latch arm 22 to maintain latch arm position whether thelatch is open or closed. The latch arm 22 engages an angle bracket 30attached to the lid 12 of the cassette. One skilled in the artrecognizes that latch components can be reversed so that the slide is onthe lid and the bracket is on the body. The subject sliding latchsuccessfully secures the lid 12 and the body 10 of the cassettetogether. The sliding spacers and positive spring tension of the latchprevent the latch from failing during sterilization and make the latcheasy to manipulate.

The sterilization cassette of the subject invention further comprises aunique rack system to hold long handled instruments that eliminates theuse of silicone and to present the sterilized instruments to a clinicianso they will not find it necessary to grab an instrument by its tip.Preferred embodiments of the subject rack system are shown in FIGS. 5-8.The rack system comprises a pair of opposing rails 32, 34. The rails aresubstantially identical in shape and in form, and are opposing in thatthey are arranged in parallel opposition to each other within thehousing of the cassette. Each rail has a series of slots to receive aportion of an instrument. The slots alternate in depth between deepslots 36 and shallow slots 38. Slots can be v-notches and/or roundedscallops. Spring fingers made from sheet stock can be used to secureirregular shaped tools. The series of alternating depth slots on onerail 32 also alternate with a series of alternating depth slots on theopposing rail 34. Therefore, a deep slot 36 on rail 32 opposes a shallowslot 38 on rail 34 in what is considered an orthogonal opposing of theslots to the parallel lengths of the rails. This allows instruments tobe placed side-by-side so that every other instrument handle is angledtoward the bottom of the box, while its immediate neighboring instrumenthandle is angled upward (see FIG. 6).

In the exemplified embodiment, a shallow, large radius scallop is shownnext to a deep, narrow radius scallop. If these scallops were all largeradius scallops the narrow peaks between the scallops on the top of therack would be pointy and sharp. Additionally, the narrow peaks would beweak and likely to bend. If the scallops were all narrow scalps then asingle-end dental instrument of typical handle size ¼ inches in diameteror larger, usually ⅜ inches round would not sit in the scallop deepenough to allow the lid to close. Thus, it is preferred that scallopwidth is varied along the rail. This combination allows the handle endof every other instrument to be held up thus giving enough spacingbetween the instrument handles to grab a single instrument with fingers.Typically, when dental instrument handles are all in the same planethere is not enough room to remove the instrument by the handle. Theonly other option is to grab the instrument by the sharp tip, whichalthough considered acceptable practice, can be dangerous. Thecrisscross rack system of the subject invention allows instruments to beclose to each other which is critical in keeping the overall cassettelength to a minimum. By just spacing the dental handles far enough apartto allow for a safer means of removing the instrument by the handle thecassette footprint would be much to long to fit into most sterilizationunits.

In a particularly preferred embodiment, rails are angled inward towardone another. The angle of the rails forces the long cylindrical dentalinstruments downward, which aids in keeping the instruments fromjiggling top to the bottom in the closed cassette. Instruments restingin an angled rail are further secured within the cassette as the lowerend of the instrument is wedged beneath the opposing angled rail. Theexemplified embodiment shows the rails angled at from about 10 degreesto about 20 degrees and preferably about 15 degrees (FIG. 7).

Top rails 40, 42 hold the bottom instruments in place when the lid onthe cassette is closed. A contoured retention rail is shown in theexemplified embodiment. Suitable retention rails can included howeverflat protruding spring fingers, a simple bar, or an angle bar. While theexemplified embodiment shows a top and lower rail to secure and holdinstruments in place it is noted that if the height of the bottominstrument rack is the same as the depth of the body 10 of the cassettethe lid 12 can serve as the retaining mechanism to hold the instrumentsin place in the rails in the closed cassette.

The rack system of the subject invention should be made ofnon-insulating materials. It is important that non-insulating materialscontact the instruments during the sterilization process. Whilestainless steel is preferred, titanium, anodized aluminum, plastic or,wire rod, or wire bar can be used to achieve the desired construction.The subject rails can be secured to the cassette by a variety of means,including, but not limited to, riveting, screwing, and spot welding. Thesterilization cassette of the subject invention can be made customizableby securing specifically configured rails to the cassette as snap inclips, or with retaining tabs on the rail.

It is understood that the foregoing examples are merely illustrative ofthe present invention. Certain modifications of the articles and/ormethods may be made and still achieve the objectives of the invention.Such modifications are contemplated as within the scope of the claimedinvention.

The invention claimed is:
 1. A rack system for a sterilization cassette,said rack system comprising: at least a first pair of matching rails,the at least first pair of matching rails being opposing rails in thatthey are adapted to be mounted in a sterilization cassette housing inparallel opposing fashion, the at least first pair of matching opposingrails being substantially identical in shape and form, each of thematching opposing rails having a height, the at least first pair ofmatching opposing rails comprising a plurality of notches along a lengthof each rail, the plurality of notches extending a depth into the heightof each rail, wherein along the length of each rail, from notch to notchof the plurality of notches, the notches alternate between a shallownotch and an immediately adjacent deep notch, a depth of the deep notchgreater than and extending further into the height of a rail then adepth of the shallow notch, and wherein when the rails are assembledinto the sterilization cassette housing, a shallow notch in one rail ofthe pair is orthogonally opposed to a deep notch in the other rail ofthe pair, whereby an instrument to be sterilized spanning the shallownotch in the one rail and the deep notch in the other rail is spacedfrom another instrument to be sterilized spanning an adjacent deep notchin the one rail and an adjacent shallow notch in the other rail to allowaccess to a handle of the instrument for removal from the sterilizationcassette.
 2. The rack system for a sterilization cassette of claim 1,further comprising a retention means to hold said instruments in placein said plurality of notches.
 3. The rack system for a sterilizationcassette of claim 2, wherein said retention means is a rail.
 4. The racksystem for a sterilization cassette of claim 3, wherein said rail ofsaid retention means has at least one notch.
 5. The rack system for asterilization cassette of claim 2, wherein said retention means is a lidof said sterilization cassette.
 6. The rack system for a sterilizationcassette of claim 1, wherein said plurality of notches are scallops ofvarying widths.
 7. The rack system for a sterilization cassette of claim1, wherein said at least a first pair of opposing rails are angledtoward one another and relative to a bottom of said cassette.
 8. Therack system for a sterilization cassette of claim 1, wherein said atleast a first pair of opposing rails are angled toward one another andrelative to a bottom of said cassette at an angle of from about 10degrees to about 20 degrees.
 9. A rack system for a sterilizationcassette, said rack system comprising: a first rail comprising aplurality of notches along a length of the first rail, the plurality ofnotches extending a depth into a height of the first rail, and along thelength of the first rail, from notch to notch of the plurality ofnotches, the notches alternate between a shallow notch and animmediately adjacent deep notch, a depth of the deep notch greater thanand extending further into the height of the first rail then a depth ofthe shallow notch; a second rail matching, the second rail comprising aplurality of notches along a length of the second rail, the plurality ofnotches extending a depth into a height of the second rail, and alongthe length of the second rail, from notch to notch of the plurality ofnotches, the notches alternate between a shallow notch and animmediately adjacent deep notch, a depth of the deep notch greater thanand extending further into the height of the second rail then a depth ofthe shallow notch; the at least first pair of matching rails beingopposing rails in that they are adapted to be mounted in a sterilizationcassette housing in parallel opposing fashion, the first and secondrails are substantially identical in shape and form; wherein when therails are assembled into the sterilization cassette housing, eachshallow notch on the first rail orthogonally opposes a deep notch on thesecond rail.
 10. The rack system for a sterilization cassette of claim9, wherein the first rail is angled toward the second rail.
 11. The racksystem of a sterilization cassette of claim 9, wherein the first rail isangled relative the bottom of the cassette at an angle of from about 10degrees to about 20 degrees and is angled toward the second rail, andthe second rail is angled relative the bottom of the cassette at anangle of from about 10 degrees to about 20 degrees and is angled towardthe first rail.
 12. The rack system of a sterilization cassette of claim9, further comprising retention means to hold an instrument in one ofthe plurality of notches.
 13. The rack system for a sterilizationcassette of claim 10, further comprising at least one retention railextending from a lid of the cassette, and at an angle relative to thelid of the cassette to match the angle of at least the first rail or thesecond rail.